Inflow Conditions and Heat Transfer From Suddenly Expanding Annular Pseudoplastic Flows
The impact of inflow conditions on flow and heat transfer in suddenly expanding annular pipe flows of a pseudoplastic fluid is studied within the steady laminar flow regime. The equations governing conservation of mass, momentum, and energy, along with the power-law constitutive model are numerically solved using a finite-difference numerical scheme. The influence of inflow conditions, annular-nozzle-diameter-ratio, k, power-law index, n, and Prandtl numbers, is reported for: Inflow Condition = {fully-developed, uniform}; κ = {0, 0.5}; n = {1, 0.6}; Re = {50}; Pr = {1, 10, 100}. Fully-developed inflows result in larger and more intense recirculation, which leads to higher wall heat transfer rates, in comparison with uniform inflows. Substantial heat transfer augmentation, downstream the plane of expansion, is only observed for Pr = 10 and 100.